Fix NPE when restoring settings from backup, where empty CSV values are
converted to null.
Add "restore from backup" from associate screen, to allow for restoring
node that has lost its association.
Allow specific SolarNode identity settings to be restored via settings
backup files, e.g. id, keystore, solarnet association details. This is
to allow the restoration of a node that has lost its identity.
Only allow restore process to restore settings starting with solarnode.
Allow larger file uploads, to allow node backup archives which can be a
bit bigger.